Too little research has examined age-related changes to conversation and interpersonal communication or how situational and environmental factors including the speech addressed to older adults limit or hinder older adults daily activities, conversational interactions, and interpersonal interactions. The expressed research will provide descriptive and experimental data concerning the syntactic complexity. Semantic content, discourse structure and acoustic characteristic of the speech addressed to older adults. Speakers are alleged to systematically modify their speech by adopting an "elderspeak" register in order to enhance communication with older adults although empirical support for this claim is limited. The specific aims are: 1. To test the hypothesis that speaker systemically modify the speech addressed to older adults with descriptive data on the psychologistic conditions. 2. To test the hypothesis that young adults systematically modify. Speech as a function of task difficulty, the perceived functional characteristics of older adults listeners and verbal cues from older adult listeners. 3. To test whether older adults are also able to modify their speech when addressing young versus older interlocutors. 4. To test the hypothesis that elderspeak enhances younger and older adults comprehension and facilitates communication. Five studies are proposed: each uses a referential communication task in which one member of attempts to convey specified information to the other member of the dyad. The speaker and listener, once they have met, are separated so that each may hear the other but cannot sec the other. Task difficulty. The perceived characteristics of the listener, the listeners' response style, and the speakers' style can be manipulated to elicit speech accommodations under naturalistic or controlled condition. This research will determine whether the speech addressed to older adults can be characterized as a special speech register and whether the used of this "elderspeak" style varies with situational and environmental factors. It will also contribute to the development of appropriate and effective speech accommodations in order to enhance and maintain older adults' conversational interactions and interpersonal relations.